ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2pPP55. Perception of multiple echoes.

Daniel D. McCall

Brian L. Costantino

Rachel K. Clifton

Dept. of Psychol., Univ. of Massachusetts, Amherst, MA 01003

Richard L. Freyman

Univ. of Massachusetts, Amherst, MA 01003

Since Ebata et al. [ 537--541 (1968)], little experimental or
theoretical work has been done on the perception of multiple echoes. In the
current experiment, listeners seated in an anechoic chamber were presented with
4-ms noise bursts in a lead-lag-lag configuration. The lead burst was presented
from a loudspeaker at 45(degrees) left of midline and one lag burst (lag A) was
presented at midline. Listeners discriminated the location of a second lag
burst (lag B) presented from a loudspeaker at either 35(degrees) or 55(degrees)
right of midline. Keeping the delay between lead and lag B constant, a range of
delays between lead and lag A was presented to determine whether changing the
delay of lag A had an effect upon the perception of lag B. Presentation of lag
A interfered with the perception of lag B over a wide range of lag A delays,
such that subjects' discrimination of the location of lag B was poorer when
compared to the discrimination of lag B when lag A was absent. The data suggest
that the introduction of an earlier echo serves to suppress directional
information from a subsequent echo. [Work supported by NIH grant DC01625.]